Pharyngeal tissues in man and rat secrete a lipase which acts in the stomach, at pH 5.4, to hydrolyze triacylglycerol to the amphipathic products diacylglycerol, monoacyglycerol and fatty acids. This first step in digestion of dietary fat facilitates emulsification of triacylglycerol. The objectives of the project are: 1) isolate and purify pharyngeal lipase from tissues in rats and other species and from pharyngeal secretions of man, 2) characterize the mode of action of pharyngeal lipase, 3) study regulation and secretion of the enzyme, and 4) determine its role in fat digestion in both normal and diseased states in infants and adults. Experiments to isolate pharyngeal lipase from serous glands of rat tongue show ten-fold purification when lipolytic activity in the 850 x g supernatant of tissue homogenates is precipitated with (NH4)2SO4 and desalted with Sephadex G-25. Lipolytic activity in the extract is stable at -20 C for several months. Assay for lipolytic activity has been improved by using an artificial emulsion of trioleoylglycerol as substrate and incubating in medium containing Ca2 ion and taurodeoxycholate instead of albumin.